(LifeWire) -- RoseEllen Dowdell wakes up in the middle of the night, thinking about her sons, one in the military and one a firefighter. Kristina Zimmerman changes the channel when she hears of another soldier killed -- not wanting to worry about her husband, a military policeman.

After losing her firefighter husband in the 9/11 attacks, RoseEllen Dowdell leads tours at the Tribute WTC 9/11 Visitor Center, located at ground zero.

For them, and for other families of firefighters, soldiers, police officers, miners or anyone else who risks death to do their jobs, anxiety is a part of life.

"It is a constant state of worry and this feeling like your stomach is in your throat," says Zimmerman, 23, a stay-at-home mother of three whose husband, Michael, searches for drugs and bombs with an Army K-9 unit. The military will be sending him to Kosovo for a year in early 2008.

"I get frustrated because, yes, I know he is just doing his job and that he is doing it for us," says Zimmerman, who lives in Miesau, Germany -- where her husband is stationed. "But at the same time I don't understand how he can put himself at risk, and our kids and me at risk of losing him as a father and husband."

Dowdell, 51, who lives in the New York City borough of Queens, knows that kind of risk intimately. Her husband, Kevin, a 20-year veteran New York City firefighter and a member of an elite rescue unit, died in the September 11 attacks on the World Trade Center.

Dowdell and her sons waited many anxious months for Kevin's body to be recovered

It was not until April 2002, when the majority of debris had been cleared from ground zero, that the Dowdell family was able to hold a memorial service and experience some kind of closure. Kevin Dowdell's body was never found.

"I think not knowing is worse," Dowdell says. "You feel out of control. I always feel I can deal with anything if I know what I'm dealing with."

Today she has her sons to worry about. James, 23, is a New York City firefighter, and Patrick, 24, a West Point graduate who is in the 4th Infantry Division, 4-42 Field Artillery, will be deployed to Iraq early next year. "I worry more about my sons (than I did about Kevin). When Patrick actually goes to Iraq, I'll be a basket case," Dowdell says.

Dowdell says that ultimately she cares most deeply about her sons' happiness. "They wouldn't be happy if they didn't do what they wanted, and if they're happy there comes a point where you can't be in control of their lives."

"You can be miserable and safe," Dowdell adds. "There's danger everywhere. Kevin used to say he was in more danger of being killed by a bus than in a fire."

Dowdell and Kristina Zimmerman have found ways to help manage their anxiety. But what is it that these families living with perpetual uncertainty actually go through -- and how do they learn to cope?

Symptoms

"The symptoms are actually very similar to anyone who is experiencing post-traumatic stress," says Elizabeth Carll, a Long Island, New York-based clinical psychologist specializing in trauma and crisis management. "It's heightened anxiety; possibly you have sleeping problems, eating problems."

Other symptoms can include headaches, irritability and withdrawal from friends and family, Carll says.

How to cope

• Stay in touch with your loved one as much as possible. Dowdell told her son, Patrick, that the first thing he needs to do when he gets to Iraq is get a cell phone. "I always feel better after I talk to them," she says. "It just brings you closer, because you're not imagining what might be going on."

• Find a support network outside your family. "The family itself is a support group, but they will certainly eventually fatigue in their own issues as well," Carll says. DailyStrength.org has more than 500 online support groups, including ones catering to military families, widows and widowers, and those suffering from post-traumatic stress disorder.

• Learn about the risks of your loved one's job. If you educate yourself, you won't be prone to thinking the worst. Dowdell reminds herself that her son James is "in a busy firehouse, which is better because he's working all the time, and the more you do the better you are at it."

• Develop stress-management strategies. Talk to your friends, go for a jog, write in your journal. Zimmerman says she talks with other wives on ArmyWifeChat on the Internet. "I also try to relax by doing scrapbooks and sewing, and sometimes just taking a walk or bubble bath."

• Seek professional help. If your stress levels are unmanageable, a therapist can help.

Today, Dowdell strives to make the most of each day, a bittersweet lesson she says she learned after September 11. "God only knows what the future holds. Make the most of your time together because it is not unlimited."E-mail to a friend

LifeWire provides original and syndicated lifestyle content to Web publishers. Jocelyn Voo is a freelance journalist and relationships editor at the New York Post. Margot Weiss is a senior editor at LifeWire.